linux/include/misc/cxl.h
Andrew Donnellan b0b5e5918a cxl: Add cxl_check_and_switch_mode() API to switch bi-modal cards
Add a new API, cxl_check_and_switch_mode() to allow for switching of
bi-modal CAPI cards, such as the Mellanox CX-4 network card.

When a driver requests to switch a card to CAPI mode, use PCI hotplug
infrastructure to remove all PCI devices underneath the slot. We then write
an updated mode control register to the CAPI VSEC, hot reset the card, and
reprobe the card.

As the card may present a different set of PCI devices after the mode
switch, use the infrastructure provided by the pnv_php driver and the OPAL
PCI slot management facilities to ensure that:

  * the old devices are removed from both the OPAL and Linux device trees
  * the new devices are probed by OPAL and added to the OPAL device tree
  * the new devices are added to the Linux device tree and probed through
    the regular PCI device probe path

As such, introduce a new option, CONFIG_CXL_BIMODAL, with a dependency on
the pnv_php driver.

Refactor existing code that touches the mode control register in the
regular single mode case into a new function, setup_cxl_protocol_area().

Co-authored-by: Ian Munsie <imunsie@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-14 20:28:11 +10:00

338 lines
13 KiB
C

/*
* Copyright 2015 IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _MISC_CXL_H
#define _MISC_CXL_H
#include <linux/pci.h>
#include <linux/poll.h>
#include <linux/interrupt.h>
#include <uapi/misc/cxl.h>
/*
* This documents the in kernel API for driver to use CXL. It allows kernel
* drivers to bind to AFUs using an AFU configuration record exposed as a PCI
* configuration record.
*
* This API enables control over AFU and contexts which can't be part of the
* generic PCI API. This API is agnostic to the actual AFU.
*/
#define CXL_SLOT_FLAG_DMA 0x1
/*
* Checks if the given card is in a cxl capable slot. Pass CXL_SLOT_FLAG_DMA if
* the card requires CAPP DMA mode to also check if the system supports it.
* This is intended to be used by bi-modal devices to determine if they can use
* cxl mode or if they should continue running in PCI mode.
*
* Note that this only checks if the slot is cxl capable - it does not
* currently check if the CAPP is currently available for chips where it can be
* assigned to different PHBs on a first come first serve basis (i.e. P8)
*/
bool cxl_slot_is_supported(struct pci_dev *dev, int flags);
#define CXL_BIMODE_CXL 1
#define CXL_BIMODE_PCI 2
/*
* Check the mode that the given bi-modal CXL adapter is currently in and
* change it if necessary. This does not apply to AFU drivers.
*
* If the mode matches the requested mode this function will return 0 - if the
* driver was expecting the generic CXL driver to have bound to the adapter and
* it gets this return value it should fail the probe function to give the CXL
* driver a chance to probe it.
*
* If the mode does not match it will start a background task to unplug the
* device from Linux and switch its mode, and will return -EBUSY. At this
* point the calling driver should make sure it has released the device and
* fail its probe function.
*
* The offset of the CXL VSEC can be provided to this function. If 0 is passed,
* this function will search for a CXL VSEC with ID 0x1280 and return -ENODEV
* if it is not found.
*/
#ifdef CONFIG_CXL_BIMODAL
int cxl_check_and_switch_mode(struct pci_dev *dev, int mode, int vsec);
#endif
/* Get the AFU associated with a pci_dev */
struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev);
/* Get the AFU conf record number associated with a pci_dev */
unsigned int cxl_pci_to_cfg_record(struct pci_dev *dev);
/*
* Context lifetime overview:
*
* An AFU context may be inited and then started and stoppped multiple times
* before it's released. ie.
* - cxl_dev_context_init()
* - cxl_start_context()
* - cxl_stop_context()
* - cxl_start_context()
* - cxl_stop_context()
* ...repeat...
* - cxl_release_context()
* Once released, a context can't be started again.
*
* One context is inited by the cxl driver for every pci_dev. This is to be
* used as a default kernel context. cxl_get_context() will get this
* context. This context will be released by PCI hot unplug, so doesn't need to
* be released explicitly by drivers.
*
* Additional kernel contexts may be inited using cxl_dev_context_init().
* These must be released using cxl_context_detach().
*
* Once a context has been inited, IRQs may be configured. Firstly these IRQs
* must be allocated (cxl_allocate_afu_irqs()), then individually mapped to
* specific handlers (cxl_map_afu_irq()).
*
* These IRQs can be unmapped (cxl_unmap_afu_irq()) and finally released
* (cxl_free_afu_irqs()).
*
* The AFU can be reset (cxl_afu_reset()). This will cause the PSL/AFU
* hardware to lose track of all contexts. It's upto the caller of
* cxl_afu_reset() to restart these contexts.
*/
/*
* On pci_enabled_device(), the cxl driver will init a single cxl context for
* use by the driver. It doesn't start this context (as that will likely
* generate DMA traffic for most AFUs).
*
* This gets the default context associated with this pci_dev. This context
* doesn't need to be released as this will be done by the PCI subsystem on hot
* unplug.
*/
struct cxl_context *cxl_get_context(struct pci_dev *dev);
/*
* Allocate and initalise a context associated with a AFU PCI device. This
* doesn't start the context in the AFU.
*/
struct cxl_context *cxl_dev_context_init(struct pci_dev *dev);
/*
* Release and free a context. Context should be stopped before calling.
*/
int cxl_release_context(struct cxl_context *ctx);
/*
* Set and get private data associated with a context. Allows drivers to have a
* back pointer to some useful structure.
*/
int cxl_set_priv(struct cxl_context *ctx, void *priv);
void *cxl_get_priv(struct cxl_context *ctx);
/*
* Allocate AFU interrupts for this context. num=0 will allocate the default
* for this AFU as given in the AFU descriptor. This number doesn't include the
* interrupt 0 (CAIA defines AFU IRQ 0 for page faults). Each interrupt to be
* used must map a handler with cxl_map_afu_irq.
*/
int cxl_allocate_afu_irqs(struct cxl_context *cxl, int num);
/* Free allocated interrupts */
void cxl_free_afu_irqs(struct cxl_context *cxl);
/*
* Map a handler for an AFU interrupt associated with a particular context. AFU
* IRQS numbers start from 1 (CAIA defines AFU IRQ 0 for page faults). cookie
* is private data is that will be provided to the interrupt handler.
*/
int cxl_map_afu_irq(struct cxl_context *cxl, int num,
irq_handler_t handler, void *cookie, char *name);
/* unmap mapped IRQ handlers */
void cxl_unmap_afu_irq(struct cxl_context *cxl, int num, void *cookie);
/*
* Start work on the AFU. This starts an cxl context and associates it with a
* task. task == NULL will make it a kernel context.
*/
int cxl_start_context(struct cxl_context *ctx, u64 wed,
struct task_struct *task);
/*
* Stop a context and remove it from the PSL
*/
int cxl_stop_context(struct cxl_context *ctx);
/* Reset the AFU */
int cxl_afu_reset(struct cxl_context *ctx);
/*
* Set a context as a master context.
* This sets the default problem space area mapped as the full space, rather
* than just the per context area (for slaves).
*/
void cxl_set_master(struct cxl_context *ctx);
/*
* Sets the context to use real mode memory accesses to operate with
* translation disabled. Note that this only makes sense for kernel contexts
* under bare metal, and will not work with virtualisation. May only be
* performed on stopped contexts.
*/
int cxl_set_translation_mode(struct cxl_context *ctx, bool real_mode);
/*
* Map and unmap the AFU Problem Space area. The amount and location mapped
* depends on if this context is a master or slave.
*/
void __iomem *cxl_psa_map(struct cxl_context *ctx);
void cxl_psa_unmap(void __iomem *addr);
/* Get the process element for this context */
int cxl_process_element(struct cxl_context *ctx);
/*
* Limit the number of interrupts that a single context can allocate via
* cxl_start_work. If using the api with a real phb, this may be used to
* request that additional default contexts be created when allocating
* interrupts via pci_enable_msix_range. These will be set to the same running
* state as the default context, and if that is running it will reuse the
* parameters previously passed to cxl_start_context for the default context.
*/
int cxl_set_max_irqs_per_process(struct pci_dev *dev, int irqs);
int cxl_get_max_irqs_per_process(struct pci_dev *dev);
/*
* Use to simultaneously iterate over hardware interrupt numbers, contexts and
* afu interrupt numbers allocated for the device via pci_enable_msix_range and
* is a useful convenience function when working with hardware that has
* limitations on the number of interrupts per process. *ctx and *afu_irq
* should be NULL and 0 to start the iteration.
*/
int cxl_next_msi_hwirq(struct pci_dev *pdev, struct cxl_context **ctx, int *afu_irq);
/*
* These calls allow drivers to create their own file descriptors and make them
* identical to the cxl file descriptor user API. An example use case:
*
* struct file_operations cxl_my_fops = {};
* ......
* // Init the context
* ctx = cxl_dev_context_init(dev);
* if (IS_ERR(ctx))
* return PTR_ERR(ctx);
* // Create and attach a new file descriptor to my file ops
* file = cxl_get_fd(ctx, &cxl_my_fops, &fd);
* // Start context
* rc = cxl_start_work(ctx, &work.work);
* if (rc) {
* fput(file);
* put_unused_fd(fd);
* return -ENODEV;
* }
* // No error paths after installing the fd
* fd_install(fd, file);
* return fd;
*
* This inits a context, and gets a file descriptor and associates some file
* ops to that file descriptor. If the file ops are blank, the cxl driver will
* fill them in with the default ones that mimic the standard user API. Once
* completed, the file descriptor can be installed. Once the file descriptor is
* installed, it's visible to the user so no errors must occur past this point.
*
* If cxl_fd_release() file op call is installed, the context will be stopped
* and released when the fd is released. Hence the driver won't need to manage
* this itself.
*/
/*
* Take a context and associate it with my file ops. Returns the associated
* file and file descriptor. Any file ops which are blank are filled in by the
* cxl driver with the default ops to mimic the standard API.
*/
struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
int *fd);
/* Get the context associated with this file */
struct cxl_context *cxl_fops_get_context(struct file *file);
/*
* Start a context associated a struct cxl_ioctl_start_work used by the
* standard cxl user API.
*/
int cxl_start_work(struct cxl_context *ctx,
struct cxl_ioctl_start_work *work);
/*
* Export all the existing fops so drivers can use them
*/
int cxl_fd_open(struct inode *inode, struct file *file);
int cxl_fd_release(struct inode *inode, struct file *file);
long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm);
unsigned int cxl_fd_poll(struct file *file, struct poll_table_struct *poll);
ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
loff_t *off);
/*
* For EEH, a driver may want to assert a PERST will reload the same image
* from flash into the FPGA.
*
* This is a property of the entire adapter, not a single AFU, so drivers
* should set this property with care!
*/
void cxl_perst_reloads_same_image(struct cxl_afu *afu,
bool perst_reloads_same_image);
/*
* Read the VPD for the card where the AFU resides
*/
ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count);
/*
* AFU driver ops allow an AFU driver to create their own events to pass to
* userspace through the file descriptor as a simpler alternative to overriding
* the read() and poll() calls that works with the generic cxl events. These
* events are given priority over the generic cxl events, so they will be
* delivered first if multiple types of events are pending.
*
* The AFU driver must call cxl_context_events_pending() to notify the cxl
* driver that new events are ready to be delivered for a specific context.
* cxl_context_events_pending() will adjust the current count of AFU driver
* events for this context, and wake up anyone waiting on the context wait
* queue.
*
* The cxl driver will then call fetch_event() to get a structure defining
* the size and address of the driver specific event data. The cxl driver
* will build a cxl header with type and process_element fields filled in,
* and header.size set to sizeof(struct cxl_event_header) + data_size.
* The total size of the event is limited to CXL_READ_MIN_SIZE (4K).
*
* fetch_event() is called with a spin lock held, so it must not sleep.
*
* The cxl driver will then deliver the event to userspace, and finally
* call event_delivered() to return the status of the operation, identified
* by cxl context and AFU driver event data pointers.
* 0 Success
* -EFAULT copy_to_user() has failed
* -EINVAL Event data pointer is NULL, or event size is greater than
* CXL_READ_MIN_SIZE.
*/
struct cxl_afu_driver_ops {
struct cxl_event_afu_driver_reserved *(*fetch_event) (
struct cxl_context *ctx);
void (*event_delivered) (struct cxl_context *ctx,
struct cxl_event_afu_driver_reserved *event,
int rc);
};
/*
* Associate the above driver ops with a specific context.
* Reset the current count of AFU driver events.
*/
void cxl_set_driver_ops(struct cxl_context *ctx,
struct cxl_afu_driver_ops *ops);
/* Notify cxl driver that new events are ready to be delivered for context */
void cxl_context_events_pending(struct cxl_context *ctx,
unsigned int new_events);
#endif /* _MISC_CXL_H */